HMPT-BOF-RH-CSP process for SPHE substrate of cold rolled deep drawing steel

Abstract

Based on hot metal pretreatment (HMPT)-basic oxygen furnace (BOF)-Rheinstahl Heraeus (RH)-compact strip production (CSP) process, parameters controlling on cold rolling deep drawing substrate SPHE were investigated during smelting and rolling process by composition design and technology control. The influence of parameters on chemical compositions, mechanical properties and microstructure was revealed by scanning electron microscope (SEM). The results show that, 1) main chemical components in SPHE are w(C)≤40×10⁻⁶, w(Si)≤ 0.01%, w(S)≤0.009%, w(N)≤20×10⁻⁶, w(O)≤ 25×10⁻⁶; 2) main mechanical properties of the SPHE are σ_s=274 MPa, σ_b=334 MPa, A=48.9%; 3) main performances of deep drawing quality (DDQ) grade steel produced by SPHE are as follows, transversely σ_s=167 MPa, σ_b=298 MPa, n=0.219, r=2.46; vertically σ_s=166 MPa, σ_b=298 MPa, n=0.226, r=2.39; in 45° direction σ_s=171 MPa, σ_b=308 MPa, n=0.214, r=2.26; 4) microstructure of DDQ is ferrite, average grain size is Grade 7.5, and inclusion size is 3–10 μm.

Keywords

hot metal pretreatment / basic oxygen furnace / compact strip production / deep drawing / hardening exponent / plastic strain ratio

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